Nicolas J.-H. Roche

The Use of a Dose-Rate Switching Technique to Characterize Bipolar Devices

The enhanced radiation sensitivity exhibited at low dose rate by many bipolar devices remains one of the main concerns for spacecraft reliability. As an accelerated test technique, a new approach based on dose-rate switching experiments has been proposed to characterize bipolar devices. The foundations of this approach are detailed and guidelines for its use are given.

Single-Event Effect Performance of a Commercial Embedded ReRAM

We show the single-event effect characteristics of a production-level embedded resistive memory. The resistive memory under investigation is a reduction-oxidation random access memory embedded inside a microcontroller. The memory structure consists of Ir top electrode, Ta2O5-δ/TaOx metal-oxide, and TaN bottom electrode. The radiation testing focused on the resistive memory array and peripheral circuits, while other portions of the microcontroller were shielded against the ion beam. We found that the resistive memory array is hardened against heavy ion and pulsed-laser-induced bit upsets. However, the microcontroller is susceptible to single-event functional interrupts due to single-event upsets in the resistive memory peripheral control circuits, which comprise of CMOS elements. Furthermore, the resistive memory architecture is not susceptible to functional failures during write, which is problematic for flash memories due to radiation-induced charge pump degradation.

Investigation and Analysis of LM124 Bipolar Linear Circuitry Response Phenomenon in Pulsed X-Ray Environment

Analog Transient Radiation Effects in Electronics (ATREE) induced by high dose-rate X-ray pulses are investigated using a flash X-ray facility. The ATREEs induced in a LM124 operational amplifier configured in three different bias configurations are investigated. A predictive methodology, based upon a previously developed ASET simulation tool, is used to model the ATREE phenomena. A semiempirical physical model is used to perform the correlation between the duration of the parasitic pulse signal induced in the LM124 and an equivalent value of the high dose-rate X-ray pulse level.

Review and Analysis of the Radiation-Induced Degradation Observed for the Input Bias Current of Linear Integrated Circuits

It is shown that the variety of shapes of the input current versus dose curve observed in several ICs is due to circuit effects, depending on the architecture, the value of the currents and the bias conditions. When stages are cascaded, the degradation of the second stage may add or subtract current to the collector current of the input transistor. The variations of the collector currents can be evaluated using the variations of the supply current. It is then possible to model the compensation effects using basic equations and study the impact of irradiation conditions. In some cases, the effect of biasing the circuit during irradiation is to reduce the compensation mechanism leading to an stronger increase in the input current. When a peak shaped degradation curve is recorded, annealing may either induce an additional degradation or a recovery depending on which side of the peak irradiation has brought the circuit.

Effectiveness of SEL Hardening Strategies and the Latchup Domino Effect

Heavy ion, neutron, and laser experimental data are used to evaluate the effectiveness of various single event latchup (SEL) hardening strategies, including silicon-on-insulator (SOI), triple well, and guard rings. Although SOI technology is widely reported to be immune to SEL, conventional pnpn latchup can occur and has been observed in non-dielectrically isolated SOI processes. Triple well technologies are shown to be more robust against SEL than dual well technologies under all conditions used in this study, suggesting that the introduction of a deep N-well is an excellent zero-area-penalty hardening strategy. A single guard ring is shown to be sufficient for SEL immunity in the 180 nm CMOS technology investigated, and is likely sufficient for more modern CMOS technologies. After triggering latchup in a certain pnpn region, latchup was observed to spread to neighboring pnpn regions, which then infected other more distant regions until it had spread over a total distance of 700 micrometers. We discuss the physical mechanism of this latchup domino effect and its implications for device characterization and hardness assurance.

Modeling and Investigations on TID-ASETs Synergistic Effect in LM124 Operational Amplifier From Three Different Manufacturers

The synergistic effect between Total Ionizing Dose (TID) and Analog Single Event Transient (ASET) in LM124 operational amplifiers (opamps) from three different manufacturers is investigated. This effect is clearly identified on only two manufacturers by three, highlighting manufacturer dependent. In fact, significant variations were observed on both the TID sensitivity and the ASET response of LM124 devices from different manufacturers. Hypotheses are made on the cause of the differences observed. A previously developed ASET simulation tool is used to model the transient response. The effects of TID on devices are taken into account in the model by injecting the variations of key electrical parameters obtained during Co60 irradiation. An excellent agreement is observed between the experimental responses and the model outputs, independently of the TID level, the bias configuration and the manufacturer of the device.

Impact of Switched Dose-Rate Irradiation on the Response of the LM124 Operational Amplifier to Pulsed X-Rays

The Synergistic effect between TID and ATREEs (Analog Transient Radiation Effects on Electronics) in an operational amplifier (opamp) (LM124) is investigated for three different bias configurations. An accelerated irradiation technique is used to study these synergistic effects. The impact of TID on ATREEs is found to be identical regardless of whether the irradiation is performed at low dose rate or whether the dose rate is switched from high to low using the Dose Rate Switching (DRS) technique. The correlation between the deviations of the opamps electrical parameters and the changes of ATREE widths is clearly established.

SEL-Sensitive Area Mapping and the Effects of Reflection and Diffraction From Metal Lines on Laser SEE Testing

Laser and heavy-ion data reveal the areas and shapes of single-event latchup (SEL)-sensitive regions in CMOS test structures and their positions relative to the affected p-n-p-n paths. Contrary to previous two-dimensional studies, this three-dimensional study shows that the position of maximum SEL sensitivity in these structures is not centered on a p-n-p-n region, but between two neighboring p-n-p-n regions, suggesting that synergistic triggering increases SEL sensitivity. The SEL-sensitivity maps suggest that laser light scattered from metal lines toward the silicon can contribute to the SEE response, for both back-side-incident two-photon absorption and front-side-incident single-photon absorption laser tests. We describe the metallization configurations and laser pulse energies for which reflected and/or diffracted laser light may contribute to the single-event effect (SEE) response.

Simulation of Laser-Based Two-Photon Absorption Induced Charge Carrier Generation in Silicon

Numerical simulation software is used to calculate quantitatively the two-photon absorption-induced carrier-density distributions generated under conditions that are experimentally relevant for single-event effects studies. The results provide valuable insight into how the magnitudes and shapes of the charge carrier distributions evolve over a large range of experimental conditions and the impacts this has for different device geometries. Furthermore, values of integrated charge are determined that can be more directly correlated with experimental observables.

Single-Event Transient and Total Dose Response of Precision Voltage Reference Circuits Designed in a 90-nm SiGe BiCMOS Technology

This paper presents an investigation of the impact of single-event transients (SETs) and total ionization dose (TID) on precision voltage reference circuits designed in a fourth-generation, 90-nm SiGe BiCMOS technology. A first-order uncompensated bandgap reference (BGR) circuit is used to benchmark the SET and TID responses of these voltage reference circuits (VRCs). Based on the first-order BGR radiation response, new circuit-level radiation-hardening-by-design (RHBD) techniques are proposed. An RHBD technique using inverse-mode (IM) transistors is demonstrated in a BGR circuit. In addition, a PIN diode VRC is presented as a potential SET and TID tolerant, circuit-level RHBD alternative.